Wear surface and seal construction

ABSTRACT

A seal construction for forming a lubricant barrier between relatively movable members including a wear or working surface on one of the members and a flexible seal element on the other member. The working surface is composed of a multiplicity of triangular asperities arranged in a simple geometric array, and these asperities are engaged by a seal face on the seal element. The depressions between the asperities permit lubricant to contact the seal face and prolong the life of the seal. Most of the triangular asperities point toward the lubricant side of the seal construction so that the sidewalls of the asperities serve as pump impellers for pumping the lubricant back toward the lubricant source. Some of the triangular asperities may be oriented in the opposite direction to maintain adequate lubricant flow underneath the seal face. The depressions may be filled with a soft filler material which during relative rotation in the presence of the lubricant wears and to a limited extent reestablishes the depressions beneath the seal face. In this manner, the depressions are maintained at an optimum depth as the asperities themselves wear.

United States Patent Dennis L. Otto Canton;

Charles M. Allen; Craig T. Walters, Columbus. all of, Ohio {72]lnvcntors [54] WEAR SURFACE AND SEAL CONSTRUCTION 23 Claims, 8 DrawingFigs.

[52] U.S. Cl 277/96, 277/134 [51] lnt.Cl F16j15/32 [50] Field of Search277/96, 133,134,153.2,154

[56] References Cited UNlTED STATES PATENTS 2,497,225 2/1970 Workman277/134 OTHER REFERENCES Zero Leakage: Results of an Advanced Lip SealTech. by R. L. Dega Paper No. 67-WA/LUB-l1, published by Journal ofLubrication Tech. pg. l- 13,.lul. 18, 1967 Primary Examiner-Laverne D.Geiger Assistant Examiner-Robert 1. Smith Attorney-Gravely, Lieder &Woodruff ABSTRACT: A seal construction for forming a lubricant barrierbetween relatively movable members including a wear or working surfaceon one of the members and a flexible seal element on the other member.The working surface is composed of a multiplicity of triangularasperities arranged in a simple geometric array, and these asperitiesare engaged by a seal face on the seal element. The depressions betweenthe asperities permit lubricant to contact the seal face and prolong thelife of the seal. Most of the triangular asperities point toward thelubricant side of the seal construction so that the sidewalls of theasperities serve as pump-impellers for pumping the lubricant back towardthe lubricant source. Some of the triangular asperities may be orientedin the opposite direction to maintain adequate lubricant flow underneaththe seal face. The depressions may be filled with a soft filler materialwhich during relative rotation in the presence of the lubricant wearsand to a limited extent reestablishes the depressions beneath the sealface. In this manner, the depressions are maintained at an optimum depthas the asperities themselves wear.

PATENTEU JUH22 19m SHEET 3 BF 3 WEAR SURFACE AND SEAL CONSTRUCTIONBACKGROUND OF THE INVENTION This invention relates in general to a wearsurface and seal construction and more particularly to a wear surfacefor supporting movable elements in engagement therewith and to a sealconstruction having such a wear surface for forming a fluid barrierbetween two relatively moving members.

Bearings and other rotating mechanisms which are normally operated in alubricating medium are generally provided with some sort of sealconstruction to prevent the lubricant from escaping the vicinity of thelubricated mechanism. Many of these seal constructions comprise anelastomeric seal element carried by one of two members which rotaterelative to one another and a rigid wear or working surface on the otherrotatable member. The elastomeric seal element bears against the workingsurface and thereby forms a barrier to the passage of lubricant acrossthe area of contact.

Heretofore, it has been considered important to have the rigid workingsurface smooth, not only to avoid leakage, but also to reduce frictionand of course the heat and wear inherent with friction. Indeed,expensive plunge grinding and polishing operations are often required toachieve this end, and such surfaces are, furthermore, subjected toexhaustive inspection procedures to insure that they do not containpits, grooves, and other surface imperfections. While a smooth wearsurface satisfactorily restricts lubricant seepage, at least at theoutset, friction is not reduced, inasmuch as lubricant flow cannot bemaintained between the surface and the seal to lubricate the sealitself. As a result, the seal heats excessively and after a short periodof operation becomes hard and brittle. This loss of resiliency, in turn,is marked by a significant decline in the ability to seal. Thus, asmooth highly polished wear surface in the long run defeats theadvantage it is supposed to provide.

SUMMARY OF THE'INVENTION One of the principal objects of the presentinvention is to provide a wear surface which permits the distribution ofa lubricant throughout the area on it which is engaged by the face of anelement movable relative thereto. Another object is to provide a sealconstruction which will overcome a great many of the present objectionsand form a durable and highly effective fluid barrier between relativelymovable members. Yet another object is to provide a seal constructionwherein adequate lubrication is provided at the seal forming contact. Afurther object is to provide a seal construction incorporating anelastomeric seal which remains resilient and does not become brittle andhard through prolonged usage. An additional object is to provide a sealconstruction which can be manufactured without resort to expensivegrinding operations and exhaustive inspection procedures. Still anotherobject is to provide a seal construction which pumps a lubricant backtoward the source of such lubricant. A further object is to provide aseal construction in which small surface imperfections at the sealinterface will not adversely affect the fluid barrier. These and otherobjects and advantages will become apparent hereinafter.

The present invention is embodied in a wear surface engaged by a face ofan element movable relative thereto. The wear surface is composed of amultiplicity of closely spaced asperities separated by an interveningsurface of a different elevation. This difference in elevation allowsthe lubricant to flow on the wear surface and contact the engaging faceof the element. The asperities may be triangular in shape and orientedto pump the lubricant in a desired direction. The invention is furtherembodied in the presence of a filler material in depressions of thesurface. The filler material is softer than the material constitutingthe asperities, and as the seal element moves relative to the wearsurface, the filler material underlying the engaging face wears, therebyreestablishing the depressions to a limited extent between theasperities. The wear is such that an optimum depression depth ismaintained as the asperities wear. The invention also encompasses theworking surface apart from the seal element. The invention also consistsin the parts and in the arrangements and combinations of partshereinafter described and claimed.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings which form partof the specification and wherein like numerals and letters refer to likeparts wherever they occur:

FIG. 1 is a sectioned perspective view of a seal construction of thecircumferential lip variety constructed in accordance with and embodyingthe present invention;

FIG. 2 is a sectional view of the seal construction shown in FIG. 1;

FIG. 3 is a fragmentary plan view showing the asperity array on theworking surface of the seal construction illustrated in FIG. I;

FIG. 4 is a fragmentary plan view showing a modified asperity array on aseal construction of the parallel face variety which also forms part ofthe present invention;

FIG. 5 is a fragmentary plan view of another modified asperity array;

FIG. 6 is a fragmentary perspective view, partially broken away and insection, of a modified seal construction of the circumferential lipvariety; I

FIG. 7 is an elevational view, partially broken away and in section, ofthe modified circumferential lip seal construction of FIG. I; and

FIG. 8 is a perspective view of the modified seal construction of FIG. 6incorporated into a parallel face seal construction.

DETAILED DESCRIPTION Referring now in detail to the drawings, and inparticular to FIG. 1, 2 designates a seal construction of thecircumferential lip variety including a rigid wear ring or segment 4having a cylindrical working or wear surface 6 which is embraced by anelastomeric lip seal 8. The seal 8 and wear ring 4 are mounted onmembers which rotate relative to one another so that the ring 4 rotatesrelative to the lip seal 8. For example, the wear ring 4 may bepress-fitted onto a rail car axle adjacent to the cones of a rollerbearing, and the seal 8 could be attached to the cup of that bearing.

More specifically, the lip seal 8 includes a body portion 10 which alongits outer periphery is bonded to a rigid seal case 12 for mountingpurposes. Inwardly therefrom the body portion 10 emerges into a pair oflips I4 and 16 which engage the wear surface 6. The lip 14 is somewhatwider than the lip 16 and forms a lubricant seal or barrier with thewear ring 4, whereas the lip 16 forms a dust seal with the wear ring 4.Thus, the oil side of the seal construction 2 is to the right of the lip14, reference being made to FIG. 1, while the air or ambient side is tothe left. The body portion 10 of the lip seal 8 is further provided withan outwardly opening circumferential groove 18 into which a garterspring 20 is fitted for urging the lip I4 snugly against the wear ring4. The lip 14 engages the working surface 6 on the wear ring 4 along agenerally cylindrical seal face 22 of axial width w (FIG. 2).

The cylindrical working surface 6 is actually composed of a multiplicityof triangular asperities 24 which are separated from one another bydepressions 26 FIGS. 1-3). In other words, the asperities 24 areseparated by an intervening surface of a lower elevation. Each asperity24 includes an outwardly presented land 28 and the lands 28 of all theasperities 24 create an interrupted surface area disposed outwardly fromthe depressed or intervening surface area created by the depressions 26.Each asperity 24 is peripherally defined by angularly related sidewalls30 and a base wall 34. The sidewalls 30 intersect at an apex 32 and abase wall 34 intersects each of the sidewalls 30 at equal angles.Accordingly, the shape of the raised land 28 of each asperity 24 is thatof an isosceles triangle. Each triangular asperity 24 forming the arrayis oriented such that its apex 32 points toward the oil side of the sealconstruction 2 and its base wall 34 extends in the direction of relativerotation between the ring 4 and the lip H4. Thus, each sidewall 30 ispresented oblique to the direction of relative rotation and, as will bepresently more fully explained, this orientation of the sidewalls 30permits them to serve as pump impellers. The asperities 24 are,furthermore, arranged to form a simple geometric array (FIG. 3), or inother words, they are arranged in successive circumferential rows withthe base walls 34 of each row in alignment and forming successivecircles about the working surface 6, while the sidewalls 32 ofasperities 24 in adjacent rows are in alignment and describe crossedhelicies across the working surface 6.

The lands 28 should cover one-third to two-thirds of the total area onthe working surface 6 across which the asperities 24 extend. Thedimensions of the asperities 24 are not critical but excellent resultshave been obtained with lands 28 ranging from about 0.005 to 0.040inches in their shortest dimension a (FIG. 3). Similarly, the asperityangle between each sidewall 30 and the base wall 34 it intersects is notcritical, but an asperity angle 0 of approximately 20 has provedacceptable for most lubricants. The depth a of the asperities 24 (FIG.2), that is the distance between the lands 28 and the bottoms of thedepressions 26, should be between I0 and 100 microinches (0.000010 to0.000100 inches). The width w of the seal face 22 should be such thatthe seal face 22 extends axially across at least three circumferentialrows of asperities 24. ln actual practice, considerably more than threerows of asperities 24 should be provided on the working surface 6 tocompensate for misalignment and flexure of the lip seal 8.

The asperities 24 may be machined into the working surface 6 of the wearring 4 with conventional cutting tools and, similarly, they may bemechanically imposed such as by knurling. Machining and mechanicaloperations, however, are often impractical since the wear ring 4 iscomposed of a hardened material to prevent excessive wear. In any event,the outer surface of the wear ring 4 may be finished prior to theformation of the asperities 24 by a through grinding operation which ismore economical than plunge grinding. The grooves resulting from thisgrinding, however, should not exceed the depth d of the asperities 24.

A particularly effective method for obtaining the desired asperityworking surface 6 on the wear ring 4 is to first mask a finished surfaceso as to provide the desired asperities 24 in relief and then chemicallyetch the exposed portions of the surface. Such masking may beaccomplished in a wide variety of ways including lithographic orphotographic techniques wherein a masked pattern is photographicallyreproduced on the wear ring surface, electrodeposition or electrostaticcoating of a desired pattern, the use of decals, or practically anymeans of providing a pattern, coat, or print that will at leasttemporarily inhibit chemical etching in preselected areas to reproducethe desired etched pattern. Any chemical etchant capable of removingmetal from the wear ring 4 whether acidic or basic in nature may beemployed. A solution consisting of 5 parts nitric acid and 95 partswater maintained at a temperature of 7075F has proved particularlysuccessful.

When the lip seal 8 and working surface 6 are at rest, the flexiblesealface 22 will tend to sink into the depressions 26. The distortion,however, is minimal due to the close spacing between the asperities 24.Leakage through the depressions 26 under static conditions is avoided byreason of the fact that the depth of the depressions 26 does not exceedthe thickness of the fluid or lubricant film. That thickness is normallyabout 100 microinches. In other words, the depressions 26 are extremelyshallow in their own right, and thereby inherently impede the passage offluid through them due to the effects of surface tension. This enablesthe seal construction 2 to serve as a very effective static barrier orseal. Thus, the leakage past the lip seal 8 when the seal construction 2is at rest is insignifi cant.

However, when the seal '8 rotates relative to the wear ring 4, the sealface 22 is lifted to the height of the cylinder defined by the lands 28and the effects of surface tension are destroyed. Consequently, thelubricant works into the depressions 26 between the asperities 24 andfills the void so defined. The lubricant within the depressions 26contacts the seal face 22 so that any given segment of the seal face 22is supplied with a thin lubricant film as it traverses an adjacent land28. Thus, the seal face 22 receives a continuous supply of lubricationwhich prevents the seal 8 from overheating, and this in turn avoidshardening of the seal 8 and the loss of flexibility which accompaniesthat hardening. Accordingly, the seal 8 remains flexible throughout longperiods of operation which would destroy a conventional seal.

The asperities 24, furthermore, break up grinding and machining patternsand thereby eliminate the tendency of such patterns and surface defectssuch as dents and scratches to pump the the lubricant across the sealface 22.

Inasmuch as the sidewalls 30 of each asperity 24 are oblique to thecircumferential path traversed by the asperity 24, the lubricant will bedeflected away from the asperity 24 in the general direction of the apex32 by the leading sidewall 30 on each asperity 24. In other words, theleading sidewalls 30 serve as pump impellers and move the lubricanttoward its source or reservoir which is at the lubricant side of theseal construction 2. The trailing sidewall 30 has no effect on thelubricant until the direction of rotation is reversed, in which case itbecomes the leading sidewall 30 and performs the pumping action. Sincethe base wall 34 is parallel to the circumferential path described byits asperity 24, it provides no pumping action whatsoever irrespectiveof the direction of rotation and, therefore, does not force thelubricant toward the air side of the bearing 2. By reason of the pumpingaction, the effectiveness of the lubricant barrier formed on the seal 20at the engagement of the lip 14 and the working surface 6 is enhanced.

In order to improve hydrodynamic load support and to prevent gutteringor grooving of the seal face 22, the axial spacing between successivecircumferential rows of asperities 24 should be reduced to a minimum.

Referring now to FIG. 4, aside from the circumferential lip sealconstruction 2, the foregoing principles may in addition be employed ina seal construction 40 of the parallel face variety. Like the sealconstruction 2, the seal construction 40 includes a working surface 42composed of a multiplicity of asperities 44 separated by depressions 46.The asperities 44, furthermore, outwardly terminate at lands 48, but thelands 48 are coplanar and perpendicular to the axis of rotation insteadof segments of a large cylinder. The working surface 42 is engagedacross the lands 48 of its asperities 44 by a seal face 50 forming partof an annular elastomeric face seal 52 (FIG. 8), and the seal face 50 issimilarly planar and perpendicular to the axis of rotation instead ofcylindrical. Thus, the asperities 44 are arranged in successive radiallyspaced rows instead of successive axially spaced rows as is the casewith the working surface 6 in FIG. ll. The same parameters regardingasperity depth d, minimum dimension a, seal face width w, and thefraction of the total area occupied by the lands 48 apply to the sealconstruction 40. Similarly, the asperities 44 are arranged in simplegeometric arrays. By reason of the arrangement in radially spaced rows,one distinction, however, is readily apparent, and that is thediminishing size of the asperities 44 in each successive row from theoutermost to the innermost row. In other words, the asperities 44closest to the axis of rotation are smallest, whereas those furthestfrom the axis of rotation are largest. In this connection, the basewalls of the asperities 44 are arcuate, and thereby form concentriccircles about the wear surface 42, but since the circumferential lengthof each asperity 44 is indeed small compared to the circumference of theseal face 42 they appear straight. Since the seal face 50 need coveronly a few circumferential rows of asperities 44, no trouble isencountered in keeping the minimum dimension a of each asperity 44between 0.005 and 0.040 inches.

The seal construction 40 operates similar to the seal construction 2,only the leading sidewalls of asperities 44 pump the lubricant generallyradially instead of axially. In the array illustrated in FIG. 4, thelubricant reservoir is located toward the axis of rotation and,consequently, the apexes of asperities 44 point in that direction. Topump in the opposite direction the orientation of the asperities 44 needonly be reversed, in which case the apexes would point radiallyoutwardly instead of inwardly.

The effectiveness of the asperities 24 insofar as the pumping action isconcerned is dependent on many factors such as the asperity angle 0, thelength of the sidewalls 30, the width of the depressions 26 betweenadjacent asperities 24, the operating speed, the lubricant viscosity,the operating temperature, the sealing force at the seal face 22, andthe thickness of the lubricant film. In some instances, these conditionsare all such that the pumping action is too effective and the outermostasperities 24 of the array and the portion of the seal face 22 whichtraverses those asperities do not receive adequate lubrication. As willbe seen by reference to FIG. 5, this lubricant starvation can beovercome by orienting a portion of the asperities 24 in the oppositedirection, that is, with their apexes 32 pointing axially outwardlytoward the air side of the seal construction 2 instead of inwardlytoward the lubricant so that they will pump in the opposite direction.This arrangement of the asperities 24 restores lubricant circulationthroughout the entire asperity array traversed by the seal face 22 sothat the seal face 22 is constantly lubricated across its entire width.Arranging the oppositely oriented asperities 24 in circumferentiallyextending sections interposed between circumferentially extendingsections of inwardly oriented asperities 24, as illustrated in FIG. 5,forms a highly satisfactory lubricant seal and has proved to be superiorto interspersing individual oppositely oriented asperities 24 among theinwardly directed asperities 24. An array having 30 percent of theasperities pointing outwardly toward the air side of the sealconstruction 2 and the remainder pointing inwardly toward the lubricantside has ap peared to be the most suitable array for railwayapplications. This pattern provided adequate lubrication to the sealface 22 by permitting circulation of the lubricant back into theasperity array, yet still eliminated leakage problems.

In a like manner, a segment of the asperities 44 forming part of theparallel face seal construction 40 (FIG. 4) may be reversed to providethe same advantages, in which case the apexes of some of the asperities44 would point radially outwardly, while others would point radiallyinwardly. Again, it is desirable to arrange the reversely orientedasperities in groups instead of randomly scattering them through thearray.

While hydrodynamic lubrication is excellent when the depth d of theasperities 24 is between to I00 microinches, these dimensions cannot bemaintained over extended periods of time where relatively high sealloads are employed, such as those generated by strong garter springs 20.This results from the fact that the wiping action of the lip seal 8across the wear ring 4 in time wears the asperities 24 until they aresubstantially obliterated and no longer effective. Of course, deeperasperities 24 on theorder of 500 microinches in depth can be used fromthe outset, but until such asperities 24 wear down to approximately 100microinches, excessive amounts of lubricant will leak through thedepressions 26. With lighter seal loads this wear problem is not nearlyso pronounced.

As illustrated in FIGS. 6 and 7, this problem is overcome by utilizing adeep etched pattern in which the asperities 24 have a true depth 1 of upto 500 microinches. The depressions 26 are subsequently filled with andthe lands 28 covered by a thin coating 60 which is less resistant towear than the material from which the wear ring 4 is formed. Plasticfiller materials are suitable for this purpose, and of all the plasticfillers tested, polyurethane containing percent by weight of microfinemolybdenum disulfide appeared to give the best results. This materialwas sprayed onto the surface 6 of the asperity etched wear rings 4.

When the wear ring 4 provided with a coating 60 of the filler materialis placed in operation, the lip 16 will, during a relatively shortrun-in period, cut a wear path 62 (FIG. 7) through the coating 60, andthat path 62 will be substantially equal in width to the width w of theseal face 22. When the lands 28 of the asperities 24 are exposed, thecoating 60 will continue to wear in the areas intermediate theasperities 24, that is at the depressions 26, until a differential ofbetween 25 and I00 microinches is established between the exposedcoating surface in the depressions 26 and the lands 28. The exact depthof this differential is the effective depth d of the asperities 24, andit is dependent on many conditions such as the flexibility of the lipseal 8, the radial seal force imparted by the garter spring 20, theconstituency of the lubricant, and the peripheral velocity of the ring4. As the asperities 24 wear through continued operation, so does thecoating 60 in the depressions 26 between the asperities 24, and thiswear is such that the same differential or effective asperity depth d ismaintained. Thus, an optimum effective depth d is maintained while theseal 20 wears through the entire 500 microinches of asperities 24, andthis requires considerable time. The optimum effective depth 11decreases rapidly as wear occurs beyond the point of obliteration of thetiller material coating 60. The asperity effectiveness is reduced as thepattern becomes less well defined and as the effective depth d decreasesduring the propagation of the pattern through the base material of thewear portion 4 until the pattern is eventually completely obliterated.Thus, after the coating 60 has worn away, the asperities 24 areselfgenerating to a limited extent.

Turning now to FIG. 8, the asperities 44 of the parallel face sealconstruction 40 may also be formed in extended lengths of up to 500microinches and then covered with a coating 70 similar in composition tothe coating 60. The seal face 50 of the seal 52 will in time wear a path64 through the coating 70 and expose the lands 48. The coating 70between the asperities 44 engaged by the seal face 50 will similarlycontinue to wear until a wear condition is reached in which theeffective asperity depth d remains somewhere between 25 and microinchesuntil the asperities 44 are obliterated.

While the asperities 24 and 44 illustrated and previously discussedherein are all of the positive variety, that is, they project outwardlyfrom an intervening surface, they may also be of the negative variety,in which case they would form individual pockets or depressions in anintervening surface and the combined outwardly presented surfaces ofthese pockets would constitute an interrupted surface area. The sealfaces 22 or 50, whatever the case may be, would therefore engage andride on the intervening surface area instead of the lands or interruptedsurface area. The pumping effect with negative asperities is the reverseof that provided by the positive asperities 24 and 44 heretoforedescribed, and, accordingly, negative asperities should be oriented withtheir apexes pointing in the opposite direction.

This invention is intended to cover all changes and modifications of theexample of the invention herein chosen for purposes of the disclosurewhich do not constitute departures from the spirit and scope of theinvention.

What we claim is:

I. A wear surface for engaging a face of an element movable relativethereto in the presence of a lubricant; said wear surface comprising amultiplicity of closely spaced lands, an intervening surface separatingthe lands and located at a different elevation from the lands so as toform a depressed portion in the wear surface, a filler material in thedepressed portion and being less resistant to wear than the lands,whereby during relative movement in the presence of the lubricant thefiller material in the depressed portion will wear and to a limitedextent will establish voids beneath the seal face so that the lubricantcan flow through the voids and lubricate the engaging face of theelement.

2. A wear surface according to claim 1 wherein the filler material is aplastic substance; and wherein the element is formed from an elastomericsubstance.

3. A seal construction according to claim il wherein the initial depthof the depressed portion exceeds I microinches; and wherein theeffective depth of the voids measured from the ends of the lands to theexposed surfaces of the filler material underlying the engaging face inthe depressed portion remains between approximately 25 and 100microinches as the lands and filler material wear due to the passage ofthe engaging face over the wear surface.

4. A wear surface for engaging an element movable relative thereto inthe presence of a lubricant; said wear surface comprising asubstantially interrupted surface area and a substantially continuousintervening surface area both presented toward the movable element, theinterrupted surface area comprising a multiplicity of closely spacedindividual surfaces substantially separated from each other by theintervening surface area so that each individual surface is generallysurrounded by the intervening surface area, one surface area beinglocated closer to and the other surface area being farther from theelement, whereby one surface area is raised and the other surface areais depressed; and a filler material covering the depressed surface area,the filler material being less resistant to wear than the material fromwhich the raised surface area is formed.

5. A wear surface according to claim 4l wherein the element is rotatablerelative to the wear surface; wherein the triangular surfaces arearranged in circumferentially extending rows; and wherein the base wallsof adjacent triangular surfaces in each circumferential row align.

6. A wear surface according to claim 5 wherein the sidewalls of thetriangular surfaces align with the sidewalls of triangular surfaces inadjacent circumferential rows so that the triangular surfaces form asimple geometric array.

7. A wear surface according to claim 5 wherein the engaging face of theelement extends across at least three circumferentially extending rows;and wherein the element is formed from an elastomeric substance.

8. A wear surface according to claim 7 wherein the interrupted surfacearea occupies approximately one-third to twothirds of the outwardlypresented surface areas of the wear surface. 7

9. A wear surface according to claim 4 wherein the intervening andinterrupted surface areas are formed on and from the same material.

10. A wear surface according to claim 9 wherein the filler materialinitially extends outwardly to at least the raised surface areas wherebyin the presence of the lubricant the filler material covering thedepressed surface area will wear and to a limited extent will establisha void beneath the element so that the lubricant can occupy the void andlubricate the face of the element which engages the raised surface area.

11. A wear surface according to claim 41 wherein the intervening surfacearea is depressed and the interrupted surface area is raised whereby theinterrupted surface area forms a plurality of lands.

12. A wear surface for engaging the face of an element movable relativethereto in the presence of a lubricant; said wear surfacecomprising asubstantially interrupted surface area and an intervening surface areaboth presented toward the face of the element, the interrupted surfacearea comprising a multiplicity of closely spaced triangular surfacesgenerally surrounded by the intervening surface area and substantiallyseparated from each other by the intervening surface area, one of thesurface areas being located closer to the movable element than the othersurface area and the distance between the two surface areas beingbetween approximately 10 microinches and 100 microinches whereby onesurface area is raised and the other is depressed, each triangularsurface being peripherally defined substantially by a base wall whichextends in the general direction of relative movement and a pair ofangularly related sidewalls which intersect at an apex pointingtransversely of the direction at relative movement, the included anglesbetween both sidewalls and the base wall being acute angles whereby thesidewalls will function as pump impellers for pumping the lubricantgenerally transversely of the direction of relative movement, thedimension of each triangular surface measured transversely of thedirection of relative movement being between approximately 0.005 and0.040 inches, the triangular surfaces being arranged in nonoverlappingrows extending in the direction of relative movement and the face ofelement traversing a plurality of the rows.

13. A wear surface according to claim 12 wherein the inter veningsurface area is depressed and the interrupted surface area is raised,whereby the interrupted surface area forms a plurality ofindividuallands.

14. A wear surface according to claim 13 wherein the sidewalls boundingthe triangular surfaces in any row align with the sidewalls oftriangular surfaces in adjacent circumferential rows so that thetriangular surfaces form a simple geometric array.

15. A wear surface according to claim 13 wherein the lands aresubstantially nondeformable and the element is formed from anelastomeric substance. I

16. A wear surface engaged by the face of an element movable relativethereto in the presence of a lubricant; said wear surface comprising asubstantially interrupted surface area and an intervening surface areaboth presented toward the movable element, the interrupted surface areacomprising a multiplicity of triangular surfaces generally surrounded bythe intervening surface area and substantially separated from each otherby the intervening surface area, one of the surface areas being locatedcloser to the movable element than the other surface area whereby onesurface area is raised and the other is depressed, each triangularsurface area being defined by a base wall extending in the generaldirection of relative movement and a pair of angularly related sidewallswhich intersect at an apex pointing transversely of the direction ofrelative movement whereby the sidewalls function as pump impellers forpumping the lubricant transversely of the engaging face of the element,a majority of the triangular surfaces having their apexes pointing inthe same transverse direction and a minority of the triangular surfaceshaving their apexes pointing in the opposite transverse direction,whereby the lubricant is distributed thoroughly across the engaging faceof the element.

17. A wear surface according to claim 16 wherein the majority oftriangular surfaces are arranged in rows extending in the direction ofrelative movement, and wherein the width of the engaging face on theelement is at least as wide as the width of three rows of triangularsurfaces.

18. A wear surface according to claim 16 wherein the intervening surfacearea is depressed and the interrupted surface area is raised, wherebythe interrupted surface area forms a plurality ofindividual lands 19. Awear surface according to claim 18 wherein the lands are relativelynondeformable, and the engaging element is formed from an elastomericmaterial.

20. A wear surface according to claim 19 wherein the element whichengages the wear surface is a flexible seal element whereby the sealelement and wear surface in combination form a seal construction havingan oil side and an ambient side; and wherein the net pumping effect ofthe sidewalls along the triangular surfaces is toward the oil side ofthe seal con struction.

21. A wear surface according to claim 16 wherein the element and wearsurface form a lubricant barrier having an oil side beyond which asupply of lubricant is maintained, and wherein the net pumping effect ofthe sidewalls along the triangular surfaces is toward the oil side.

22. For use in forming a lubricant barrier with a flexible elastomericseal element having a seal face; a wear surface formed from a rigidmaterial and engaged by the seal face; said wear surface comprising amultiplicity of closely spaced triangular lands and an interveningsurface generally surrounding each land and substantially separating thelands from each other, both the lands and the intervening surface beingpresented toward the seal element face with the intervening surfacebeing located further from the seal element face than the lands so as toform a depression between the lands for enabling the lubricant to passunder and lubricate the seal face when the wear surface and element moverelative to each other, the effective distance between the lands and theintervening surface being between approximately 10 and approximately 100microinches, each triangular land being peripherally defined by a basewall extending generally in the direction of relative movement betweenthe wear surface and seal element and a pair of angularly relatedsidewalls located oblique to the direction of movement between the wearsurface and seal element, the sidewalls intersecting at an apex pointingtransversely of the direction of relative movement and the includedangle between each sidewall and the base wall being an acute angle; thetriangular lands being arranged in rows extending in the direction ofrelative movement, the base walls of the lands in each row being inalignment and the apexes of the lands in each row pointing in the samedirection, the width of three successive rows of lands being less thanthe width of the seal face whereby the seal face will traverse at leastthree rows of triangular lands.

23. The structure according to claim 22 wherein the sidewalls of thetriangular lands of one row align with the sidewalls of triangular landsof the adjacent rows so that the triangular lands form a simplegeometric array.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,340Dated June 2 1971 Inventor(s) Dennls L Otto et a1 It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Q11 the cover sheet "References Cited", "2,497,225" should read3,497,225

Signed and sealed this 2nd day of May 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents FORM (msgJ USCOMM-DC wave-P69 UIS, GOVERNMENY PRINTING OFFICE1989 0-355-33

1. A wear surface for engaging a face of an element movable relativethereto in the presence of a lubricant; said wear surface comprising amultiplicity of closely spaced lands, an intervening surface separatingthe lands and located at a different elevation from the lands so as toform a depressed portion in the wear surface, a filler material in thedepressed portion and being less resistant to wear than the lands,whereby during relative movement in the presence of the lubricant thefiller material in the depressed portion will wear and to a limitedextent will establish voids beneath the seal face so that the lubricantcan flow through the voids and lubricate the engaging face of theelement.
 2. A wear surface according to claim 1 wherein the fillermaterial is a plastic substance; and wherein the element is formed froman elastomeric substance.
 3. A seal construction according to claim 1wherein the initial depth of the depressed portion exceeds 100microinches; and wherein the effective depth of the voids measured fromthe ends of the lands to the exposed surfaces of the filler materialunderlying the engaging face in the depressed portion remains betweenapproximately 25 and 100 microinches as the lands and filler materialwear due to the passage of the engaging face over the wear surface.
 4. Awear surface for engaging an element movable relative thereto in thepresence of a lubricant; said wear surface comprising a substantiallyinterrupted surface area and a substantially continuous interveningsurface area both presented toward the movable element, the interruptedsurface area comprising a multiplicity of closely spaced individualsurfaces substantially separated from each other by the interveningsurface area so that each individual surface is generally surrounded bythe intervening surface area, one surface area being located closer toand the other surface area being farther from the element, whereby onesurface area is raised and the other surface area is depressed; and afiller material covering the depressed surface area, the filler materialbeing less resistant to wear than the material from which the raisedsurface area is formed.
 5. A wear surface according to claim 4 whereinthe element is rotatable relative to the wear surface; wherein thetriangular surfaces are arranged in circumferentially extending rows;and wherein the base walls of adjacent triangular surfaces in eachcircumferential row align.
 6. A wear surface according to claim 5wherein the sidewalls of the triangular surfaces align with thesidewalls of triangular surfaces in adjacent circumferential rows sothat the triangular surfaces form a simple geometric array.
 7. A wearsurface according to claim 5 wherein the engaging face of the elementextends across at least three circumferentially extending rows; andwherein the element is formed from an elastomeric substance.
 8. A wearsurface according to claim 7 wherein the interrupted surface areaoccupies approximately one-third to two-thirds of the outwardlypresented surface areas of the wear surface.
 9. A wear surface accordingto claim 4 wherein the intervening and interrupted surface areas areformed on and from the same material.
 10. A wear surface according toclaim 9 wherein the filler material initially extends outwardly to atleast the raised surface areas whereby in the presence of the lubricantthe filler material covering the depressed surface area will wear and toa limited extent will establish a void beneath the element so that thelubricant can occupy the void and lubricate the face of the elementwhich engages the raised surface area.
 11. A wear surface according toclaim 4 wherein the intervening surface area is depressed and theinterrupted surface area is raised whereby the interrupted surface areaforms a plurality of lands.
 12. A wear surface for engaging the face ofan element movable relative thereto in the presence of a lubricant; saidwear surface comprising a substantially interrupted surface area and anintervening surface area both presented toward the face of the element,the interrupted surface area comprising a multiplicity of closely spacedtriangular surfaces generally surrounded by the intervening surface areaand substantially separated from each other by the intervening surfacearea, one of the surface areas being located closer to the movableelement than the other surface area and the distance between the twosurface areas being between approximately 10 microinches and 100microinches whereby one surface area is raised and the other isdepressed, each triangular surface being peripherally definedsubstantially by a base wall which extends in the general direction ofrelative movement and a pair of angularly related sidewalls whichintersect at an apex pointing transversely of the direction at relativemovement, the included angles between both sidewalls and the base wallbeing acute angles whereby the sidewalls will function as pump impellersfor pumping the lubricant generally transversely of the direction ofrelative movement, the dimension of each triangular surface measuredtransversely of the direction of relative movement being betweenapproximately 0.005 and 0.040 inches, the triangular surfaces beingarranged in nonoverlapping rows extending in the direction of relativemovement and the face of element traversing a plurality of the rows. 13.A wear surface according to claim 12 wherein the intervening surfacearea is depressed and the interrupted surface area is raised, wherebythe interrupted surface area forms a plurality of individual lands. 14.A wear surface according to claim 13 wherein the sidewalls bounding thetriangular surfaces in any row align with the sidewalls of triangularsurfaces in adjacent circumferential rows so that the triangularsurfaces form a simple geometric array.
 15. A wear surface according toclaim 13 wherein the lands are substantially nondeformable and theelement is formed from an elastomeric substance.
 16. A wear surfaceengaged by the face of an element movable relative thereto in thepresence of a lubricant; said wear surface comprising a substantiallyinterrupted surface area and an intervening surface area both presentedtoward the movable element, the interrupted surface area comprising amultiplicity of triangular surfaces generally surrounded by theintervening surface area and substantially separated from each other bythe intervening surface area, one of the surface areas being locatedcloser to the movable element than the other surface area whereby onesurface area is raised and the other is depressed, each triangularsurface area being defined by a base wall extending in the generaldirection of relative movement and a pair of angularly related sidewallswhich intersect at an apex pointing transversely of the direction ofrelative movement whereby the sidewalls function as pump impellers forpumping the lubricant transversely of the engaging face of the element,a majority of the triangular surfaces having their apexes pointing inthe same transverse direction and a minority of the triangular surfaceshaving their apexes pointing in the opposite transverse direction,whereby the lubricant is distributed thoroughly across the engaging faceof the element.
 17. A wear surface according to claim 16 wherein themajority of triangular surfaces are arranged in rows extending in thedirection of relative movement, and wherein the width of the engagingface on the element is at least as wide as the width of three rows oftriangular surfaces.
 18. A wear surface according to claim 16 whereinthe intervening surface area is depressed and the interrupted surfacearea is raised, whereby the interrupted surface area forms a pluralityof individual lands.
 19. A wear surface according to claim 18 whereinthe lands are relatively nondeformable, and the engaging element isformed from an elastomeric material.
 20. A wear surface according toclaim 19 wherein the element which engages the wear surface is aflexible seal element whereby the seal element and wear surface incombination form a seal construction having an oil side and an ambientside; and wherein the net pumping effect of the sidewalls along thetriangular surfaces is toward the oil side of the seal construction. 21.A wear surface according to claim 16 wherein the element and wearsurface form a lubricant barrier having an oil side beyond which asupply of lubricant is maintained, and wherein the net pumping effect ofthe sidewalls along the triangular surfaces is toward the oil side. 22.For use in forming a lubricant barrier with a flexible elastomeric sealelement having a seal face; a wear surface formed from a rigid materialand engaged by the seal face; said wear surface comprising amultiplicity of closely spaced triangular lands and an interveningsurface generally surrounding each land and substantially separating thelands from each other, both the lands and the intervening surface beingpresented toward the seal element face with the intervening surfacebeing located further from the seal element face than the lands so as toform a depression between the lands for enabling the lubricant to passunder and lubricate the seal face when the wear surface and element moverelative to each other, the effective distance between the lands and theintervening surface being between approximatelY 10 and approximately 100microinches, each triangular land being peripherally defined by a basewall extending generally in the direction of relative movement betweenthe wear surface and seal element and a pair of angularly relatedsidewalls located oblique to the direction of movement between the wearsurface and seal element, the sidewalls intersecting at an apex pointingtransversely of the direction of relative movement and the includedangle between each sidewall and the base wall being an acute angle; thetriangular lands being arranged in rows extending in the direction ofrelative movement, the base walls of the lands in each row being inalignment and the apexes of the lands in each row pointing in the samedirection, the width of three successive rows of lands being less thanthe width of the seal face whereby the seal face will traverse at leastthree rows of triangular lands.
 23. The structure according to claim 22wherein the sidewalls of the triangular lands of one row align with thesidewalls of triangular lands of the adjacent rows so that thetriangular lands form a simple geometric array.